Agricultural land expansion is a solution to address global food security challenges in the context of climate change. However, the sustainability of expansion in arid countries is difficult because of scarce surface water resources, groundwater salinity, and the health of salt-affected soil. Developing expansion and sustainability plans for agriculture requires systems thinking, considering the complex feedback interactions between saline groundwater, salt-affected soil, plant growth, freshwater mixing with saline groundwater, irrigation systems, and the application of soil amendments to alleviate the salinity impacts. This study presents an extensive literature review on the effects of salinity on soil and plant health, the constraints and opportunities for sustainable agriculture in Egypt, and a systems thinking approach to the feedback interactions between saline water, salt-affected soil, and the application of soil amendments to achieve required crop yields. Insights and strategies are discussed, including a system-dynamics-based decision model, irrigation systems with diversified and decentralized water sources, urban water demand management, energy availability, smart irrigation systems, and active participation of stakeholders to achieve sustainable agriculture under climate and socioeconomic changes. The insights are expected to encourage stakeholders and academic communities in the water, agriculture, and related food security sectors to develop a quantitative and systematic decision-making framework for sustainable agriculture systems in arid regions.

The goal of this study is to assess the use of saline groundwater in combination with soil amendments to increase the efficiency of wheat production in new agricultural soil in Egypt. The experiment was conducted during the two consecutive growing seasons, 2019/2020 and 2020/2021, at the Shandaweel Agricultural Research Station, Sohag, Egypt. In this study, plants of Shandaweel 1 spring bread wheat cultivar were grown under the combinations of the two water treatments, i.e., freshwater (307.2 ppm) and saline water (3000 ppm (NaCl + MgCl₂)) representing groundwater in Egypt delivered by drip irrigation and the two biochar rates, i.e., zero and 4.8 ton/ha as a soil amendment. The cob corn biochar (CCB) was synthesized by using the slow pyrolysis process (one hour at 350 °C). The results revealed that saline water reduced the grain yield ratio by 8.5%, 11.0%, and 9.7% compared to non-saline water during seasons 2019/2020 and 2020/2021 and over seasons, respectively. Concerning, combined over seasons, the biochar addition enhanced the grain yield by 5.6% and 13.8% compared to non-biochar addition under fresh and saline irrigation water conditions, respectively. Thus, the results indicated and led to a preliminary recommendation that saline groundwater is a viable source of irrigation water and that biochar seemed to alleviate salinity stress on wheat production and in reclaimed soils of Egypt.

Drought stress is one of the main environmental challenges that dramatically reduce global rice production within several agricultural ecosystems. Breeding drought-tolerant rice genotypes is an important sustainable strategy to overcome this constraint. In this work, drought tolerance levels were assessed according to biochemical, anatomical, and molecular aspects, which led to selecting three promising crosses (Sakha 107 × Sakha super 300, Sakha 107 × M206, and Sakha 107 × Sakha 108) that were compared with their parents as controls. The antioxidant capabilities of the chosen potential crosses, such as the ascorbate peroxidase activity (APX), superoxide dismutase activity (SOD), catalase activity (CAT), and total phenolics, were significantly higher compared with their parents under drought stress. Moreover, the promising selected crosses could accumulate greater proline and chlorophyll contents. The potential superiority of the three selected rice crosses was anatomically represented throughout cross-sections of roots, stems, and leaves, which recorded higher values of cross-section diameter, epidermal thickness, cortex thickness, mesophyll thickness, and bundle sheath thickness as well as a broader range of xylem vessel diameters than their parents under a water deficit. The observed superiority of the antioxidant activities in the overall drought-tolerance mechanisms and anatomical characteristics reflected their protective role in the adaptation process under water stress. Molecular analyses using inter-simple sequence repeat (ISSR) markers suggested two promising crosses (Sakha 107 × Sakha super 300 and Sakha 107 × M206) to be the most suitable crosses for saving water. They had the highest similarity values and were grouped in a distinct cluster. The relative gene expression of OsACS2, OsCML31, OsCYP94C2a, and OsSRO1c was significantly elevated in the two selected drought-tolerant rice genotypes (Sakha 107 × Sakha super 300 and Sakha 107 × M206).